NKK Wins Award for High-speed Rotating Arc Welding Technology
NKK Corporation of Japan has been awarded the 1994 Minister of International Trade and Industry Invention Prize and Invention Practice Service Prize by the Japan Institute of Invention and Innovation. The award is in recognition of NKK's development and commercial application of automatic high-speed rotating arc welding technology.
Receiving the awards at the annual invention award ceremony in Tokyo in the presence of Japan's Emperor and Empress are NKK's President Shunkichi Miyoshi and the four- member research team led by Yuji Sugitani. "This is excellent recognition for NKK, as developers of the world's first high-speed rotating arc welding process. NKK has licensed the technology to welding machine makers. It is being widely applied in automated welders and robots and is contributing to improved industrial productivity," said Mr T Goda, general manager of NKK Singapore representative office.
The technology is a gas-shielded metal arc welding process, in which the electrode wire tip is positioned in an eccentric pattern. The process is unique because the arc rotates at 10-100 cycles per second due to the rotation of the electrodes either in a coaxial or conical motion (both methods have been patented). The high speed rotation decentralises the arc force and reduces arc pressure, which produces a flat weld bead and uniform welding quality.
The invention of this technology ensures faster and more efficient welding with highly improved detection accuracy of the arc sensor and greatly reduced welding defects, and has therefore become a key technology in the promotion of welding robotisation.
Following the technology's invention in 1979, it was then used in welding heavy thick plate. Subsequently, applications were expanded to include pressure vessels and various machinery, cutting welding cost significantly by 90%. NKK's patent applications for the technology number 119 in Japan and 57 overseas, with 38 and 31 patents, respectively, granted to date.
Since 1988, NKK has licensed the patented technology for application in the shipbuilding, steel-frame, boiler and automobile industries and has sold a total of 146 systems at home and overseas. A milestone was recorded in 1992-1993 when the 26 welding robots incorporating CAD-CAM systems, installed at the steel bridge fabricating shop of NKK's Tsu Works, achieved complete unmanned operation.
NKK Corporation, Japan's second largest steelmaker, is a diversified company specialising in steelmaking, heavy industries, shipbuilding, advanced materials and urban development, electronics and biotechnology.
